Bipolar crossed-field device including electromagnetic coils of the same polarity

Abstract

Bipolar crossed-field device 10 has outer electrode 12 and inner electrode 18 which define interelectrode space 16. Magnetic field coils 46, 48 operate together to form a magnetic field in the interelectrode space 16 shaped to trap electrons for cascading ionization and plasma formation when viewed from either electrode.

I claim: 
     
       1. A bipolar crossed-field switch device comprising: first and second spaced electrodes defining an interelectrode space therebetween, said electrodes being cylindrical and said interelectrode gap being annular, said first electrode being the outer electrode and said second electrode being the inner electrode, said electrodes being shaped so that said space is a continuous closed annular path;   means for enclosing said space so that a selected gas in an amount insufficient for self-sustained cascading ionization in the presence of an electric field and in the absence of a magnetic field and in sufficient quantity so that ions therein ionize in the presence of the electric field and a magnetic field of proper strength and shape so that cascading ionization can be maintained therein;   first and second annular electromagnetic coils of the same polarity positioned exteriorly of said outer first electrode so that each said magnetic field coil produces a first region of negative curvature in said interelectrode space when viewed from said outer first electrode, and a second region of positive curvature in said interelectrode space therebetween, so that when a potential is applied to said electrodes with said first electrode negative, said first region of negative curvature can trap electrons to cause cascading ionization and the formation of conductive plasma in the interelectrode space and so that when a negative potential is applied to said second electrode, said second region of positive curvature in said interelectrode space when viewed from said first electrode causes trapping of electrons so that cascading ionization and the formation of an electrically conductive plasma occurs in the interelectrode space so that said crossed-field switch device is conductive in either polarity.